Arc extinguishing means for high voltage circuit breakers



June 14, 1960 A. s. CASWELL ARC EXTINGUISHING MEANS FOR HIGH VOLTAGE CIRCUIT BREAKERS Filed May 6, 1953 9 Sheets-Sheet 1 a g 3M JrramviVs June 14, 1960 A. s. CASWELL 2,941,060

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June 14, 1960 A. s. CASWELL 2,941,060

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ARC EXTINGUISHING MEANS FOR HIGH VOLTAGE CIRCUIT BREAKERS Filed May 6, 1955 9 Sheets-Sheet 9 v [2/ dz zz /20 A24 /20 E. 54 J15. 5 C 05 I24 2:

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United States Patent Arthur S. Caswell, Philadelphia, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa. I

Filed May 6, 1953, Ser. No. 353,281

4 Claims. (Cl. 200-144) My invention relates to novel are chutes for high voltage circuit breakers having an interrupting capacity of over 250 mv. a. and is more particularly directed to novel construction and design for the arc plates thereof and is an improvement of the arc extinguishing means shown in US. Patent Nos. 2,613,299 and 2,646,481.

Circuit interrupting equipment, as is well known in the art, must have arc extinguishing means in order to cool off and deionize the are which is formed between the movable interrupting contacts.

For relatively low voltageapplication, the arc plates of the arc extinguishing means are usually metallic memhers which are used to substantially cool the arc and to prevent restriking thereof. However, for high voltage circuit interrupting equipment, for which my invention is directed, it is necessary to use spaced insulating arc plates in order to divide the are into a plurality of series paths to thereby more rapidly extinguish same.

Many structural arrangements for the arc plate and are chute are known in the prior art. One prior art arrange ment provides a unitary structure wherein a comb like arrangement contains both the spacers and the arc plates of the arc chute. In this type of arrangement, the intricacy of the configurations of the arc plates plus the precision requirements of the spaced parallel plates have resulted in a decided disadvantage due to the molding problems encountered for these complex structures.

Thus, I propose an arrangement wherein the arc plates of the interrupting means are all individual units which may be assembled to form an arc chute having all of the advantages of the prior art comb-like arc structure but none of the disadvantages thereof. That is, by providing individual arc plates, the necessity for a complex molding and the intricacies of spacing are overcome.

Another type of prior art arrangement provides individual arc plates in which two half sections are provided to interweave in order to form each plate of the arc chute. That is, each plate comprises two separate sections which are properly aligned together to effect a single arc plate.

In my arrangement, each assembly is a unitary molding thereby limiting the number of parts required for the arc chute and also simplifying the mold requirements for the plates.

Although the obvious disadvantages and objections to the unitary structure of spacers and plates can be overcome by the above mentioned prior art arrangement of removable and replaceable arc plates within an arc structure, no satisfactory arrangement has heretofore been available in which support means are provided for the full length of the are plates, simplification of the plates to be used in the arc chute or elimination of the spacers. Thus, for example, in some of the prior art arrangements, independent spacers were provided so that each arc plate could be inserted separately into the grooves provided therefor. However, even though this arrangement overcomes many of the disadvantages encountered with a unitary comb-like structure it adds the disadvantage of having the position of the slots in the spacers predeterice process and thus it is not possible to vary or increase the pressure on the arc plates and thus, in the event the slots were over-sized it was impossible to firmly secure the arc plates within the arc chute. Also, even though this arrangement eliminated the necessity of molding a large complex unitary arc plate spacer arrangement, it still required that the spacer means for the arc plates be molded in a unitary structure thereby resulting in the usual disadvantages encountered in molding complex configurations.

With the novel arc plate and structural arrangement of my invention, it is possible to compensate for any possible inaccuracies in the molding by providing an arrangement wherein the support pressure of the arc plates can be adjusted after the plates have been assembled.

Furthermore, my invention provides an arc plate construction of relatively small and simple design which can be molded without the necessity of a complex mold.

It will be further noted that in prior art arrangements, removable and replaceable are places were made from a ceramic material which had to be fired before the plate could be used. Thus, it was impossible to provide an arrangement with integral flanges, to be used as spacers, on the arc plate since the firing would introduce undue stress and strain therein. Accordingly, the prior art arrangement for removable and replaceable arc plates required that the plate be made flat with attached asbestos strips to serve as webs or spacers therefor.

The novel are plate of my invention is made from a glass mica material which can be either machined or molded and hence, integral flanges can be provided since the firing operation is eliminated. The glass mica material used in my invention becomes semi-molten at 1800 F. and hence can be pressed into the desired shape of the mold due to the plastic flow when high pressure is applied.

Severalembodiments of my invention are set forth in the opening description. In the first embodiment, separate and independent spacer means are provided for each arc plate in such a manner that the spacers at one side serves as a positioning means for its associated arc plate and as a spacer for the two adjacent arc plates. Thus, this means not only serves as a spacer and support for its associated arc plate but also serves in coordination with other spacer means as a spacer and support for the adjacent arc plates. In this arrangement, the spacer is made of a soft material so that it can absorb the shock and prevent breakage of the brittle arc plates.

In a second embodiment of my invention, each arc plate is molded with a web or flange means to serve as spacers so that the removable and replaceable arc plates can be pancaked on top of each other and still maintain the spaced parallel relationship. In this arrangement, the flange extends for the entire length of the arc plate so that spacing and supporting means are provided for the full length to thereby add structural support to the plates when they are exposed to undue arc gas pressures during interruption. Thus, with this arrangement, the plates are designed and molded in such a manner that the individual spacers and associated arc plates are a unitary structure thereby eliminating the necessity of having separate and independent spacer units.

My invention proposes several modifications for the design of the arc plate. Although the arc plate of my invention is to be used primarily with a center slot type arrangement, I propose one modification wherein a single arc plate is provided with the center slot and also provide another modification wherein each arc plate is provided with a slot or triangular section cut at one edge thereof. In this latter arrangement, the cooperation of two plates form a single center slot for the arc chute. It will be noted, however, that even though it requires two are plates to form a single center slot arrangement, each plate mined by the molding 3 traverses the .entire width of the are oh te. Hence, the center slot effect is achieved due to the lateral alignment of the spaced arc plates rather than the transverse alignment thereof.

Several modifications .of this embodiment are :possible so as to'accomplish such advantages as staggered center .slot arrangement and/or providea configuration for the plates whereby a single design can be used forall of the 'arc plates of the structure.

Accordingly, a primary object of my invention is to provide a glass mica arc plate structure having integral flanges extending the entirelength thereof to serve as spacer and support means. I

Another object of my invention is to provide an arc :plate construction which does not have-to be'fired and hence, has no undue stress orstrain.

Another object of my invention is to provide an arc plate arrangement in which the plates areremovable and interchangeable thereby eliminating the necessity of a complex molding.

A still further object of my invention is to provide arc extinguishing means for high voltage circuit breakers wherein each arc plate is a unitary structure.

A still further object of my invention is to provide a *staggered'center slot arc extinguishing means in which the spacing and supporting of the arc plates is achieved bythe webs or flanges which are an integral part of the plates. A still'further object of my invention is to provide an arc chute means which maintains all of theadvanta'ges of the prior'ar t arc chutes andovercomes all of 'the disadvantages thereof.

Still another object'of my invention is' to provide an arcchute-arrangement which isrelative'ly cheapto manufacture and economical to assemble.

A "further object of my invention is to provide an arrangement'utilizing flat arc plates with spacers made of soft material to thereby absorb shocks and prevent breakage'of the 'arc plates. 7

Anotherobject of my invention is to provide spacer mean's'in' such a manner that they serve to support and position theirassociated plate and also the adjacent plates. I Still another object of my invention is to-proVide a removable and replaceable'arc plate arrangement'in which the pressure between the. platescan be altered and varied after the unit has been assernbled. I "Still another" object of invention is to provide a high voltage circuit breaker -ar c chute which c an belconifsti-ucted from individual molded parts whereby each of the parts used therein is simple in design to therebyeliminate the necessity of complex molds.

A further object of my invention is to provide novel are plates and arrangements therefor whereby individual spacer means can be completely eliminated.

A still further object of'my inventionis' to provide a novel configuration for arcplates in which a single design can be used for each of the arc plates.

A further object of myinvention is to provide an arc chute arrangement in which the right hand and left "hand plates have identical construction and configuration and can be readily and easily interchanged. '7 I A' further object of my invention is to provide a structural arrangement for are chutesto be used with high voltage circuitbreak ers whereby the arc plateshave a configuration to enable-same to be used as are plates and spacers.

"These and other objects of my invention will heap! parent from the following description when .taken in conneetion with the drawings in which:

Figure laisuan illustration of a typical 'high voltage circuit breakershowing' an arc chute positioned in close proximity to the cooperating contacts. Figure lb is a schematic cut away view showing tlrepar c plates invention positioned within an arc chute of the type shown in Figure 1a.

Figure 2 shows a first embodiment of my invention wherein fiat arc plates are used in coordination with independent spacer means. In these figures, Figure 2a is a top view of the flat arc. plate and spacers when positioned within an arc plate; Figure2b is an end view taken in the direction of the arrows 2b2 b of Figure 2a; Figure 2c is a view taken in the direction of the arrows 2c--2c of Figure 2a;':1sigure 222?:is aside view of one of the flat arc plates used in the are chute of Figure 2a; Figure 2e is an end viewer the arc plateshown in Figure 2d; andFigure 2f is'a top view of the arc plate shown in Figure 2d.

Figure 3 shows asecon'dem'bodiment of my invention wherein the cross-sectional view of the arc plate is L- shaped. In this embodiment, and in those following shown in Figures 4, 5, 6, 7 and 8, the independent spacer means are eliminated and integral flanges or webs are provided on the .arcplateto serve as support and spacing means. In these ifigures, Figure 3a is atopview of a plurality of arcplatestpositioned in an'arc chute; Figure 3b.is:aview'taken'inthe direction of the arrows 3b-3b of'Figure 3a;.Figure 3c is a viewitaken in the direction of the arrows ic 3c ofFigure 3a; Figure 3d is a side view of thearc plate used in Figure 3c; Figure 3e is an end view of the arc plate shownin Figure 3d; Figure 3f is a top view of'the arc plates shown in Figure 3d.

Figure 4a is still another modification of the arc plate of Figures 3, 4 and 5 in which Figure 8 is a top view of the spaced parallel arc plates;'Figure 4b is a view taken in the direction of the arrows -4b-4b of Figure 4a; Figure 4c is a view taken in the direction of the arrows 4c4c of 'Figure 4a;Figure 4d is a side view of the arc plate of Figure-4agFigure 4e-is-a left end view of the arc plate of Figure td; Figure 4f is a right end view of the arc plate of Figure 4d and Figure 4g is a top view of the arc plate of Figure 4d.

' lFigure 'S shows a second modification of the arc plate 'of Figure 3. In this'arrangement the cross-sectional area of the arc plate is a non-uniform I. The configuration of the-slot or cutaway-section (if-this arc plate is similar tothat shown-in Figures 3 and 6 wherein a center slot effect is achieved'by properly-positioning the arc plates. In this figure, Figure 5a represents a top view of a plurality of parallelspaced right and left "hand arc plates; Figure 'ib'isa view taken'in the direction'of the arrows 5b-'f 5bfofFigure 5a; Figure Sois a viewtaken in'the directionof the arrows 5c-"-5cot .Figure'5a;'Figure 5a is a side view 'of the arc plate used in the arc chute of V Figure 5 a ;'Fi gure Se is an end view taken along the line arc plate of FigureSd.

Figure '6' shows a modificationof'the arc plate in the embodiment ofFigure 3 wherein the crosssectional view thereof is T shaped; In these'figures, Figure 6a is. a top view of a plurality of spaced parallelT-shaped 'arc'plates within an arc chutegF-igure 6b: is a" view taken in the direction Qf'the arrows lib- 617 of Figure 6a; Figure 6c is asideview taken inpthe direction of the arrows 60-60 of Figure 6a;Figur'e 6d is a side view of the arc plate of Figure 6a,; Figure 62 is an end view of the arc plate of Figure'od andFigureGf is a top view of the arc'plate r Figureed.

Figure 7 is a third ernbodiment of my invention wherein eachjarc plate is {provided with a centerslot and the "cross-sectional'views therebyxare U-shaped. With'this arrangement, twof fi gures of arc pl-ates arere'quired for th alternate ljight' and left hand arc plates. .IIlfthBSQrfiQ t res, F igu're 7i; represent'sa top view of the spaced parallel .arcjplates in an' are chute;"Figur'e 7b is a view taken inithejdirectionfof the arrows 7b-f-7l of 'Fi'gure7a; Figure 7c a view takenin the directionof the arrows 7c"7c of Figure 711; Figure. 7d isa side viewof one of Figure 7a; "gure 7e a. .leftendview ate of Figure '7iiffiig'tlre 7f.[..is a right end view of the arc plate of Figure la and Figure 7gis a top view of the arc plate of Figure 7d.

Figure 8 is a modification of the arc plate shown in Figure 7. In this arrangement, each arc plate is provided with a center slot and, the cross-section of the plates are I-shaped. With the modification of these figures, a single configuration of an arc plate is required for each of the plates of the are chute irrespective of its position therein. In these figures, Figure 8a represents a top view of the plurality of arc plates when in parallel spaced relation Within an arc chute; Figure 8b is a view taken in the direction of the arrows 8b8b of Figure 8a; Figure 8c is a view taken in the direction of the arrows 8c8c of Figure 8a; Figure 8d is a side view of one of the arc plates used in the arc chute of Figure 8a; Figure Se is an end view of the arc plate of Figure 8d; and Figure 8 is a top view of the arc plate of Figure 8d.

Referring now to Figure 1a, I have shown a high voltage circuit breaker 10 which may be supported in any suitable manner, as for example on back panel 1 1. The back panel 11 carries an upper back connecting stud 15 and a lower back connecting stud 16 mounted in any suitable manner thereon by means of insulators 115, 116. The upper back connecting stud 15 carries at the right hand end thereof a stationary contact structure 17 comprising arcing contact 18 and a main stationary contact 19.

The arcing and main contacts 18 and 1 9 are supported in any -suitable manner in the contact structure 17 and are biased toward the movable contact elements 45, 46 by any suitable manner such as a compression spring.

The arc chute structure 50 provided with arcing horns 51, 52 is attached to the back panel 11 and positioned above the main contacts 19, 46 and arcing contacts 18, 45 so that the are created therebetween during contact separation will move into the arc extinguishing structure.

My invention is' particularly directed to the arc plates 120 of the arc chute and is not directed to the arc chute per se. The arc chute 50 is constructed with side sheets 53 and 54, as best seen in Figure lb in which the arc plates are positioned perpendicular thereto. The plurality of arc plates 120 positioned within the arc chute 50 are rectangular in shape and positioned between the side plates 53 and 54 in such a manner that the path of movement of the movable contact arm 25 moves in a plane including at least a portion of the center slot created by the plates.

The first embodiment of the arc plate arrangement which may be used in the arc chute 50 of Figure 1b is shown in Figure 2. In this arrangement, the arc plate 59 is provided with an off center slot 68 and is flat on all surfaces. Spacer means such as 60, 61, 62, 63 and 64 are provided to support and position the arc plate similar to 59. The spacing means 60, 61, 62, 63, 64, are elongated U-shaped members made of a soft material so as to prevent shock and breakage of the arc plates. A spacing means is provided for each of the arc plates, i.e., spacer means 64 is associated with the arc plate 56 and the spacer means 62 is associated with the arc plate 57.

The groove in each spacing means such as 60 is sufficiently wide to receive the side edge of the arc plate 58. Hence, as seen in Figure 2a, the groove of spacer 63 receives the left edge of the arc plate 59, and adjacent thereto, a groove in spacer 60 receives the side edge of the arc plate 58. Thus, it will be noted that the left end of alternate plates such as 56 and 58 are positioned between adjacent spacers such as 64 and 60.

Thus, it will be apparent that support and spacing means are provided for each side of the arcing plates 55, 56, etc. By providing independent support spacers such as 61 and 64, 62 and 63 and supporting one end of the arc plates in the groove associated thereto and the other end between adjacent spacer means, the supporting pres- 6 sure on the entire arc chute means can be altered and adjusted after the unit has been assembled. That is, as best seen in Figure 2, pressure can be applied on both ends of the arc structure to thereby move the plurality of arc plates either closer together or further apart.

It will be noted that the spacer means 62, 63, 64, etc., extends for the entire length of the arc plates and hence, proper spacing and supporting means are provided therefor. This is a necessary requirement for high voltage circuit breakers to provide maximum support and strength for the arc plates to resist the high pressure created by the arc gasses following circuit interruption. It will be further noted that with the design shown in Figure 2, that a design of an arc plate similar to that shown in Figure 2d can be used for each of the arc plates within the arc chute. Thus, for example, the arc plate 59 can be positioned within the arc chute 50 with the slot 68 closest to the side sheet 53 and the arc plate 58 can be positioned within the arc chute 50 with the slot 68 closer to the side sheet 54. Thus, with this arrangement a staggered center slot arrangement, as seen in Figure 2b, can be achieved by having the so called right and left hand are plates identical in design and configuration.

A second embodiment of my invention is shown in Figures 3 and 4. In this arrangement, as is true of the arrangement shown in Figures 5 through 8, the independent spacer means such as 61, 62 and 63 of Figure 2 is eliminated. In this embodiment, I provide a novel configuration for the arc plates whereby flanges form an integral part of the arc plate thereby eliminating the necessity of independent and separate spacer means.

The are plates of Figures 3 through 8 are made of a glass bonded mica which becomes semi-molten when I properly heated so that any desirable configuration can be formed due .to the plastic flow when it is subjected to high pressures. Since the glass bonded mica does not have to be fired, there will be no undue stress or strain set up in the web or flanges if cooled slowly.

In the arrangement shown in Figure 3, the arc plate 70 is constructed with a .web or flange 71 and a recess portion on its opposite side. With this arrangement, a right hand are plate will be the mirror image of the plate shown in Figure 3d. Thus, for example as seen in Figure 3a, a plurality of arc plates 70 can be positioned in spaced parallel relationship by having the web or flange 71 of any one are plate extend through the recess or slot opening 73 of its adjacent arc plate to thereby serve as a support and spacing means for the next alternate arc plate, as best seen in Figure 30.

It will be noted that in the embodiment of Figures 3 and 4, a notch is cut from one side of the arc plates and hence, the center slot effect is achieved with adjacent plates which alternately have either left or right hand notches facing the side sheets 54 and 53, respectively. Thus, the center slot effect is achieved as seen in Figure 3b.

Figure 4 shows a design and configuration for are plates in which the flange member 102 emanates from the lower portion of the arc plate rather than the upper portion, as shown in Figure 3. Thus, in the use of the biasing of the arc plate 100, as shown in Figure 4, the right and left hand plates will not be identical. That is, the right hand plate will have to be a mirror image of the plate shown in Figure 6d.

In the design of the type of arc plate shown in Figure 4, molded webs 101-102-103 are an integral part of the plate and the entire unit has a U-shaped crosssectional area as seen in Figure 4g. The lower web 102 is twice as wide as its associated upper web 103, as seen in Figure 4e, whereas the web 101 is the same width as the web 103. In this arrangement, it is apparent that it is necessary to construct a right and left hand are plate so that they may be properly arranged as best seen in Figures 4a, 4b and 40. As seen in Figure 6c, the web 102 will protrude in the opening of the adjacent are plate and can thereby be used as a support therefor and as a spacer for the alternate arc plate whereas the webs 101 and 1 i 3 will serve as spacers for an adjacent are plate. p

A modification of the arcplates of Figures 3 and 4 is shown in Figures 5 and'fi. In this arrangement, the extending flanges are symmetrical with respect to the right and left hand side of the arc plate. Thus, for example, as seenin Figure 5e, the space and supporting flange 93 and 94 extend on the right and left hand side, respectively, of the arc plate 90 and in Figure 6'; the flanges 31 and 82 extend from the left and right hand side, respectively, from the arc plate 80.

With the arrangement of Figures 5 and 6, the arc plate, similar to that shown in Figures 3 and 4, is used although this arrangement has the advantage of the'interchangeability 'of 'the right and left hand arc plates. The manner in which the webs and flanges serve to support and space the various arc plates is best seen and understood from the figures. Thus, using Figure 6 as an example, a plurality of arc plates titl are interwoven due to the configuration of the webs 81, 82, 83 and 84' in such a manner that the other webs 83 and 8d serve as spacers and supports for adjacent arc plates thereof and the webs 31 and 82 serve as spacers and supports for the alternate arc plates thereof.

in like manner, the webs 91, 92, 95 and )6 of Figure 5 will-serve as supports and spacers for the adjacent arc plates whereas the Wider lower webs 93 and 94v Will serve as spacers and supports for alternate arc plates.

Still another embodiment of my invention is shown in Figure 7 wherein the glass bonded mica arc plate 110 is provided with a center slot and has a U-shaped crosssectionai area in which the webs 111 and 112 extend from both ends thereof toward only one side and are of uniform thickness or depth. It will be noted that with this configuration, the right and left hand are plates will have different construction so that alternate are plates will be a mirror image of the plateshown in Figure 7d. With this arrangement, the flanges 110 and 112 will serve as a support and spacer means for an adjacent arc plate.

A modification of the center slot arc plate of Figure 7 is shown in Figure 8. In this arrangement, the crosssectional area of the plate 12%) is I-shaped and is formed by the flanges 124, 122, 123 and 124. These four webs 12 1, 122, 123- and 12d protrude from each side at each end of the plate so that the cross-sectional area is I-shaped.

Thus, it will be apparent from the View shown in Figures 8a, 8b and Be that the left and right hand are plates will be identical in construction so that it is only necessary to mold one are plate to be used as either a right or left hand plate. That is, in the assembly of the arc chute shown in Figure 8a, the first arc plate would be positioned as shown in Figure 8a, the one adjacent thereto would be rotated 180 from the position shown in Figure 8d and hence, the staggered center slot arrangement as shown in Figure 8b can be achieved. As seen in Figure 8a, the'extending flanges 121, 12 2 and 123, 124 serve as spacers and supports for the adjacent arc plates.

In summary, it will be noted that I have provided an arc plate construction and design in which either independent spacing means can be provided for flat arc plates or glass bonded mica arc plates can be provided with integral flanges wherein the flanges can serve as the support and spacing means for adjacent and alternate arc plates.

In the foregoing, I have described my invention only in connection with preferred specific embodiments thereof. Many variations and modifications of the principles of my invention within the scopeof the description herein are obvious. Accordingly, I prefer to be bound not by the specific disclosure herein but only by the appending claims.

I claim; I

1. Are extinguishing means for a high voltage circuit interrupter comprising a plurality of spaced parallel glass bonded mica arcplates; said arc plates having four integral flanges extending for the entire length; each of said flanges serving as spacing means for adjacent arc plates; said .arc plates having a center slot; said arc plates removably and replaceably mounted in an arc chute, said center slots forming a channel for the are extending in a directionperpendicular to said spaced parallel plates;

.2. Arcextinguishing means for ahigh voltage circuit interrupter comprising a plurality of spaced parallel glass bonded mica arc plates; said are plates having four integral flanges extending for the entire length; said flanges serving as spacing means for adjacent arc plates; said are plateshaving a center slot; said are plates forming arc extinguishing'rneans when positioned in spaced parallel relationship; adjacent arc plates having said slots disposed on opposite sides of a center line; said slots creating a staggered center slot arrangement when said are plates are mounted in spaced parallel relationship.

3. An arc extinguishing means for a high voltage circuit interrupter carrying a plurality of independent spaced parallel arcplates'said arc plates being provided with an opening at one and therein to provide an entrance for an are positioned perpendicular to said plates; each of said plates being provided with two integral flanges extending for the entire length of each side thereof along an edge thereof to serveand function as spacers from the next adjacent plates, each of said plates being supported on both ends by the coaction of said flanges with said plates.

4. An arc extinguishing means for a high voltage circuit interrupter comprising a plurality of independently spaced parallel, arc plates; said arc plates being provided with opening at one end therein to provide an entrance for an arc positioned perpendicular to said plates;

each of said plates comprising a thin elongated member having a first edge and a second edge, two integral flanges projecting from both sides of each of said plates adjacent to said first and second edges and extending for the full length thereof to serve and function as a spacer separating each of said plates from the next adjacent plates; each of said plates being supported by said flanges along both said first and said second edges.

References Cited in the file of this patent UNITED STATES PATENTS 

